As it is an AndroidOne device,google provide support for only Chromecast devices.Lets wait for Miracast support in a future update.
7 months ago
HMD have chosen the stock Android / Android One path. Personally, that is a major reason why I'm interested in their products. That means being extremely closely aligned to Google on most features. Google deprecated Miracast in Android Marshmallow 6.0, in favour of Google Cast / Chromecast. I believe Sony support Chromecast, so you might find a solution there.